<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            width: 200px;
            height: 200px;
            background-color: rgb(187, 150, 156);
        }
    </style>
</head>
<body>
<div id="app">
    <!-- 写死，不能变 -->
    <div class="box" style="width: 400px;height: 400px;background-color: green;"></div>
    <hr>
    <!-- 能变 -->
    <div class="box" :style="{width:'400px',height:'400px',backgroundColor:'green'}"></div>
</div>
<script src="./vue.js"></script>
<script>
    const app = new Vue({
        el: '#app',
        data: {}
    })
</script>
</body>
</html>